Vacuum insulated door construction

ABSTRACT

A method of fabricating a refrigerator cabinet or door includes forming a wrapper and an inner liner. The method further includes forming a vacuum insulated core comprising a permeable core material that is disposed inside an impermeable envelope. A sheet of prefabricated compressible foam material is positioned between the vacuum insulated core between the inner door liner and/or the door wrapper. The prefabricated compressible foam material may be cut from a sheet of foam having substantially uniform thickness prior to fabrication of the refrigerator door. The foam compresses to accommodate differences in spacing between the vacuum insulated core and the door wrapper and/or the door liner.

BACKGROUND OF THE INVENTION

Refrigerators typically include a refrigerated cabinet having one ormore openings that can be selectively closed off by doors that aremovably mounted to the cabinet. The doors are typically insulated, andseal off the openings when in a closed position. A known type ofconstruction utilized in fabricating refrigerator cabinets and doorsincludes an outer wrapper and inner liner having an interior cavity orspace that is filled with insulating foam. The foam may comprise apolyurethane foam that is injected into the space after the wrapper andliner are interconnected. The foam expands to fill the interior spaceprior to curing.

Another type of insulated cabinet construction includes vacuum insulatedinternal panels. Vacuum insulated panels provide improved insulatingproperties whereby the cabinet walls can be thinner, yet retain the sameinsulation properties. However, known vacuum insulated refrigeratorcabinet and door constructions may suffer from various drawbacks.

SUMMARY OF THE INVENTION

A method of fabricating a refrigerator cabinet or door includes forminga wrapper having a peripheral edge portion. An inner liner having aperipheral edge portion is also formed. The wrapper and liner maycomprise an outer door panel (“door wrapper”) and an inner door liner.The method further includes forming a vacuum insulated core comprising apermeable core material that is disposed inside an impermeable envelope.The envelope is evacuated to form a vacuum inside the envelope. A sheetof prefabricated compressible foam material is positioned between thevacuum insulated core between at least one of the inner door liner andthe door wrapper. The method includes securing at least a portion of theperipheral edge portion of the door wrapper to the peripheral edgeportion of the inner door liner with the vacuum insulated corepositioned between the door wrapper and the inner door liner. Theprefabricated compressible foam material may be cut from a sheet of foamhaving substantially uniform thickness prior to fabrication of therefrigerator door. The foam compresses to accommodate differences inspacing between the vacuum insulated core and the door wrapper and/orthe door liner. Because the space between the vacuum insulated core andthe wrapper and the space between the insulated core and the liner ispreferably quite small to provide a thinner door construction, it isdifficult to inject conventional foams (e.g. polyurethane) into thislimited space. The use of a prefabricated compressible foam sheeteliminates gaps that would otherwise exist, and also provides supportfor the wrapper and/or liner to reduce flexing/bending that couldotherwise occur due to a gap between, for example, the door wrapper andthe vacuum insulated core.

These and other features, advantages, and objects of the presentdisclosure will be further understood and appreciated by those skilledin the art by reference to the following specification, claims, andappended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an isometric view of a refrigerator;

FIG. 2 is an exploded isometric view showing a refrigerator door havinga vacuum insulated core and one or more prefabricated foam sheets;

FIG. 3 is an isometric view showing a vacuum insulated core prior tofolding into a three dimensional shape as shown in FIG. 2;

FIG. 4 is a fragmentary cross sectional view taken along the line IV-IV;FIG. 3;

FIG. 5 is a partially schematic cross sectional view of the refrigeratordoor taken along the line V-V; FIG. 1; and

FIG. 6 is a partially schematic cross sectional view of a refrigeratordoor having a vacuum insulated core and preformed foam sheet.

DETAILED DESCRIPTION

For purposes of description herein, the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” and derivativesthereof shall relate to the invention as oriented in FIG. 1. However, itis to be understood that the disclosed subject matter may assume variousalternative orientations and step sequences, except where expresslyspecified to the contrary. It is also to be understood that the specificdevices and processes illustrated in the attached drawings, anddescribed in the following specification, are simply exemplaryembodiments of the inventive concepts defined in the appended claims.Hence, specific dimensions and other physical characteristics relatingto the embodiments disclosed herein are not to be considered aslimiting, unless the claims expressly state otherwise.

With reference to FIG. 1, a refrigerator 1 includes an insulated cabinet2 having internal spaces 4 and 6 with openings 8 and 10, respectively ona front side 12 of cabinet 2. In the illustrated example, the interiorspace 4 comprises a fresh food refrigerated space that can be accessedby opening one or both doors 14 and 16, and the interior space 6comprises a freezer compartment that can be accessed by opening drawer18. Drawer 18 includes an insulated front panel 20. It will beunderstood that the term “door” as used herein generally refers to amovable door (e.g. doors 14 and 16) or an insulated panel 20 on amovable drawer 18. It will be understood that the construction/method offabricating door 16 as described herein is equally applicable to thedoor 14 and front panel 20 of drawer 18.

With further reference to FIG. 2, door 16 includes an outer skin orwrapper 22, a liner 24 and a vacuum insulated core 26. As discussed inmore detail below, a prefabricated foam sheet 28 may be positionedbetween liner 24 and vacuum insulated core 26. A prefabricated foamsheet 30 may also be positioned between the wrapper 22 and vacuuminsulated core 26. Door 16 may include only foam sheet 28, only foamsheet 30, or both foam sheets 28 and 30.

Outer wrapper 22 may comprise sheet metal or polymer that is formed toprovide a desired 3D shape utilizing known processes. The wrapper 22 mayinclude a central area 32 that is generally planar, and side walls34A-34D that extend transversely from the central area 32. The sidewalls 34A-34D may include inwardly-extending flanges 36A-36D that areconfigured to interconnect with liner 24. The wrapper 22 may optionallyinclude one or more openings 38 that may be utilized to mount a userdisplay 40 and/or an ice and/or water dispenser 42 (FIG. 1).

Liner 24 is preferably made by thermoforming a sheet of polymer materialutilizing known thermoforming. Liner 24 may also be made utilizing aninjection molding process. The liner 24 includes a central portion 44and sidewall portions 46A-46D. The side walls 46A-46D may includeconnecting structures or flanges 48A-48D that are configured to engagethe flanges 36A-36D and/or side walls 34A-34D of wrapper 22. Theconfigurations of the peripheral edge portions 50 and 52 of wrapper 22and liner 24 may have various known configurations, and are generallyconfigured to be interconnected to one another in a known manner.

The vacuum insulated core 26 may include a central area 54 and sidewalls 56A-56D. With further reference to FIGS. 3 and 4, the vacuuminsulated core 26 may be fabricated from a flat sheet of core material26A having flaps 58A-58D that are folded along fold lines 60A-60D,respectively to form side walls 56A-56D, respectively. With reference toFIG. 4, the panel 26A comprises a permeable core material 62 that isdisposed inside an impermeable envelope 64 that is sealed along a seam66. The envelope 64 is evacuated to form a vacuum. In a preferredembodiment, the core material comprises fiberglass, silica powder, orother suitable material, and the envelope 64 comprises one or morelayers of foil and/or polymer. V-shaped notches 68A-68D may be formedutilizing a V-shaped forming tool 70 to thereby provide fold lines60A-60D. As discussed in more detail below, additional layers of corematerial 90 may be utilized to provide increased thickness in specificregions if required for a particular application.

Referring again to FIG. 2, the vacuum insulated core 26 is configured tofit closely within wrapper 22, with side walls 56A-56D of vacuuminsulated core 26 being disposed directly adjacent, but inside sidewalls 34A-34D, respectively, of wrapper 22. Liner 24 is configured tofit within vacuum insulated core 26 in a nesting manner, with centralportion 44 of liner 24 disposed immediately adjacent central area 54 ofvacuum insulated core 26, and with side walls 46A-46D of liner 24 beingdisposed adjacent and inside of, side walls 56A-56D of vacuum insulatedcore 26.

Due to manufacturing tolerances, and the like, gaps may be present in atleast some regions between liner 24 and vacuum insulated core 26.Similarly, gaps may also exist between wrapper 22 and vacuum insulatedcore 26 in some regions. To account for such gaps, prefabricated foamsheet 28 and/or prefabricated sheet 30 may be positioned between vacuuminsulated core 26 and liner 24 and/or between vacuum insulated core 26and wrapper 22. The prefabricated foam sheets 28 and 30 preferablycomprise a compressible foam material having a thickness of about0.060-1.0 inches, and more preferably about 0.125-0.375 inches. The foamsheets 28 and 30 may comprise a known foam material that isprefabricated in sheets having uniform thickness, and the sheets 28 and30 may be cut to size as required for a particular application. Examplesof suitable foam materials include polyethylene, EVA (Ethylene-vinylacetate) and polyurethane. The prefabricated foam sheets 28 and 30preferably have sufficient stiffness to significantly reduce or preventflexing of liner 24 and/or wrapper 22, respectively if a user applies anout of plane force to the liner 24 or wrapper 22. However, prefabricatedfoam sheets 28 and 30 also preferably have sufficientresilience/compressibility to permit some compression during theassembly process to thereby account for variations in the gap betweenliner 24 and core 26, and variations in the gap between wrapper 22 andcore 26. Typically, the gaps between the components are selected to bethe same size or smaller than the thicknesses of sheets 28 and 30 evenif the gaps are at a maximum possible size due to tolerances in thecomponents such that sheets 28 and 30 are compressed at least somewhatand completely fill the gaps.

During assembly, the wrapper 22 may be positioned in a lower tool orfixture 72. If a prefabricated foam sheet 30 is to be installed betweenvacuum insulated core 26 and wrapper 22, the prefabricated foam sheet 30is cut to size. The prefabricated foam sheet may optionally beadhesively attached to the wrapper 22 and/or the vacuum insulated core26. The adhesive may comprise hot melt adhesive, two-part adhesive, orother suitable adhesive. The prefabricated foam sheet 30 may be sizedand configured such that an edge portion 78 of foam sheet 30 is foldedalong a rectangular fold line 76 during assembly whereby the edgeportion 76 is disposed between side walls 34A-34D of wrapper 22 and sidewalls 56A-56D of vacuum insulated core 26. It will be understood thatthe prefabricated foam sheet 30 may be cut to remove corner portions ofsheet 30 to form flaps to prevent bunching/overlap at the corners in amanner that is similar to the flaps 58A-58D of vacuum insulated corematerial 26A as shown in FIG. 3.

If a prefabricated foam sheet 28 is to be utilized in the assemblyprocess, the foam sheet 28 is cut to size, and positioned between liner24 and vacuum insulated core 26. The foam sheet 28 may be adhesivelysecured to liner 24 and/or to vacuum insulated core 26. The adhesive maycomprise hot melt adhesive, two-part adhesive, or other suitableadhesive. The foam sheet 28 may also be cut and folded along fold line80, whereby the edge portion 82 of prefabricated foam sheet 28 may bepositioned between side walls 56A-56D of vacuum insulated core 26, andside walls 46A-46D of liner 24.

An upper tool or fixture 74 may then be utilized to press the wrapper 22and liner 24 together. The lower tool 72 and upper tool 74 may beconfigured to ensure that the peripheral edge portions 50 and 52 ofwrapper 22 and liner 24 are engaged with one another. The peripheraledge portions 50 and 52 may be sealed and/or interconnected utilizingvarious suitable known techniques. The assembled door may then beremoved from the fixtures 72 and 74.

With reference to FIG. 5, a door 16A includes a wrapper 22A, liner 24A,and a vacuum insulated core 26A. The door 16A includes a prefabricatedfoam sheet 28A, and may also optionally include a prefabricated foamsheet 30A. The wrapper 22A is preferably formed from sheet metal (e.g.stainless steel) utilizing known metal forming processes, and the innerliner 24A is formed from a polymer material. The liner 24A may befabricated by thermoforming a sheet of polymer material. The peripheraledge portion 50A of wrapper 22A comprises an inwardly-extending flange.The peripheral edge portion of liner 24A comprises anoutwardly-extending flange 52A that overlaps the flange 50A of wrapper22A. During assembly, the flanges forming the peripheral edges 50A and52 are interconnected and sealed utilizing known processes.

With further reference to FIG. 6, a refrigerator door 16B includes ametal wrapper 22B, and a polymer liner 24B. Liner 24B may be formed froma sheet of polymer material utilizing a thermoforming process. Aprefabricated foam sheet 28B is positioned between the liner 24B and thevacuum insulated core 26B. A prefabricated foam sheet 26B may optionallybe positioned between wrapper 22B and vacuum insulated core 26B. Thevacuum insulated core 26B includes side wall portions 84 and 86. Theside wall portions 84 have an increased thickness “T,” and fit withinside walls 88 of wrapper 22B. The increased thickness of side wall 84may be formed by stacking an additional strip 90 (FIG. 3) of vacuuminsulated core material to the side walls of the vacuum insulated core26B. The end portion 86 of the side wall may comprise a single layer ofvacuum insulated core material. For example, the flaps 58A-58D (FIG. 3)may have a width “W1,” and the strips 90 may have a width “W2” that issignificantly less than the width “W1.”

Referring again to FIG. 6, the liner 24 may include an end portion 92that is U-shaped or J-shaped, whereby the end portion 92 extends aroundthe end portion 86 of the side walls of vacuum insulated core 26. Duringassembly, the peripheral edge portion 50B of wrapper 22B issealed/attached to peripheral edge portion 52B of inner liner 24B. Theperipheral edge portions 50B and 52B may comprise overlapping flangesthat are pressed together by upper and lower tool fixtures 74, 72,respectively (FIG. 2) in a known manner.

It is to be understood that variations and modifications can be made onthe aforementioned structure without departing from the concepts of thepresent disclosure, and further it is to be understood that suchconcepts are intended to be covered by the following claims unless theseclaims by their language expressly state otherwise.

What is claimed is:
 1. A method of fabricating a refrigerator door, themethod comprising: forming a door wrapper having a peripheral edgeportion; forming an inner door liner having a peripheral edge portion;forming a vacuum insulated core comprising a permeable core materialthat is disposed inside an impermeable envelope, wherein the envelopehas been evacuated to form a vacuum inside the envelope; positioning asheet of prefabricated compressible foam material between the vacuuminsulated core between at least one of the inner door liner and the doorwrapper; securing at least a portion of the peripheral edge portion ofthe door wrapper to the peripheral edge portion of the inner door linerwith the vacuum insulated core positioned between the door wrapper andthe inner door liner.
 2. The method of claim 1, wherein: the sheet ofcompressible foam material has a uniform thickness prior to assembly ofthe refrigerator door.
 3. The method of claim 2, wherein: at least aportion of the compressible foam material is compressed between thevacuum insulated core and the inner door liner.
 4. The method of claim1, wherein: the door wrapper defines a central portion; the inner doorliner defines a central portion; at least a portion of the vacuuminsulated core is sandwiched between the central portions of the innerdoor liner and wrapper when the refrigerator door is assembled.
 5. Themethod of claim 1, wherein: the sheet of compressible foam material issandwiched between the vacuum insulated core and the inner door liner.6. The method of claim 5, wherein: the door wrapper and the inner doorliner have rectangular perimeters that are substantially equal in sizeand shape; the sheet of compressible foam material has a rectangularperimeter disposed adjacent the rectangular perimeters of the doorwrapper and the inner door liner.
 7. The method of claim 1, wherein: thesheet of compressible foam material is sandwiched between the vacuuminsulated core and the door wrapper.
 8. The method of claim 1, wherein:the vacuum insulated core includes a generally flat central portion anda pair of spaced apart side walls extending transversely from thecentral portion whereby the vacuum insulated core is generally U-shapedin cross section.
 9. The method of claim 8, wherein: the inner doorliner has a central portion and spaced apart side walls extendingtransversely from the central portion whereby the inner door liner has aU-shape in cross section, and wherein the inner door liner rests insidethe vacuum insulated core.
 10. The method of claim 9, wherein: the sheetof compressible foam material is disposed between the inner door linerand the vacuum insulated core and includes a central portion disposedbetween the central portions of the vacuum insulated core and the innerdoor liner, and edge portions that are disposed between the side wallsof the vacuum insulated core and the inner door liner.
 11. The method ofclaim 1, wherein: the sheet of compressible foam material has an initialthickness, before fabrication of the refrigerator door, of about 0.125inches to about 1.0 inches.
 12. The method of claim 1, wherein: the doorwrapper is fabricated from sheet metal; the inner door liner isfabricated by thermoforming a polymer sheet.
 13. The method of claim 1,wherein: the vacuum insulated core is folded to form a 3D shape.
 14. Themethod of claim 1, wherein: the sheet of compressible foam material isadhesively secured to at least one of the vacuum insulated core, thedoor wrapper, and the inner door liner.
 15. The method of claim 14,wherein: adhesive is applied to at least one of the sheet ofcompressible foam material, the door wrapper, and the inner door liner,before the peripheral edge of the door wrapper is secured to theperipheral edge of the inner liner.
 16. A vacuum insulated refrigeratordoor, comprising: a door wrapper having a peripheral edge; a vacuuminsulated core comprising a permeable core material that is disposedinside an impermeable envelope, wherein the envelope has been evacuatedto form a vacuum inside the envelope, and wherein the vacuum insulatedcore is sandwiched between the door wrapper and the door liner; a doorliner having a peripheral edge that is secured to the peripheral edge ofthe door wrapper; a sheet of compressible foam material disposed betweenthe vacuum insulated core and at least one of the door wrapper and theinner door liner, wherein the sheet of compressible foam material iscompressed in at least one region due to a reduced spacing between thevacuum insulated core and at least one of the door wrapper and the doorliner.
 17. The vacuum insulated refrigerator door of claim 16, wherein:the compressible foam material is adhesively secured to at least one ofthe vacuum insulated core, the door liner, and the door wrapper by alayer of adhesive.
 18. The vacuum insulated refrigerator door of claim16, wherein: the vacuum insulated core includes a central portion andedge walls extending transversely from the central portion.
 19. Thevacuum insulated refrigerator of claim 18, wherein: the liner includesedge wall portions overlying the edge walls of the vacuum insulatedcore.
 20. The vacuum insulated refrigerator of claim 19, wherein: theedge walls of the vacuum insulated core define distal edges; and theedge wall portions of the liner have generally U-shaped portions thatwrap around the distal edges.